It may be the lesbians who get top billing in this impish comedy horror, but it's the sparks that fly between James Corden and Mathew Horne which really set the screen alight. Of course that anxious homoeroticism is also key to the success of BAFTA-winning sitcom Gavin & Stacey and lays the groundwork for their new sketch show, conveniently hitting TV screens just as this film arrives in cinemas. Still, even without all the hype, the natural warmth between Horne and Corden proves to be the magic ingredient in a supernatural romp that would otherwise be too silly for its own good.

Obviously, with a title like Lesbian Vampire Killers, the actors come to this with tongue in cheek and (sadly for the pervs) not in any other orifice. But that's not for want of trying. Flabby sex-starved Fletch (Corden) convinces Jimmy (Horne) to come away on holiday and get his mind off being dumped, but that's only because he hopes to snare some bikini-clad totty for himself. Alas, their meagre budget only stretches to a hiking trip in the Norwich countryside and specifically ye olde village of Cragwich. Little do they know it's a hotbed of lesbian vampire activity, which means they risk getting their blood sucked and nothing else to compensate.

Fletch and Jimmy are blissfully unaware of the danger they're in, especially when a camper van full of pretty foreign students rolls across their path. Following in a long tradition of horror movies and Scooby Doo cartoons, they end up staying the night at a lonely cottage where even the portraits on the wall have spying eyes. Then the girls start to go missing… Scooby Doo may be the most apt point of reference as Claydon directs to a comic strip vibe, right down to the on-screen captions. Horne is always ready with a comically nonplussed facial expression and Corden - like the famous cartoon mutt - flaps his jowls and makes funny whimpering noises.

There's more comedy than creepiness (never too much gore), and the titular vampires give the film a cool edge as well. Inspired by the paintings of Luis Royo, they look spectacular; as if they've floated off the cover of a Heavy Metal album. Just by putting them in the same frame, Fletch and Jimmy appear even geekier. Crucially, the joke is always on them, regardless of accusations that might be levelled by knee-jerking gay rights activists. Jimmy then morphs into a classic romantic hero after bookish virgin Lotte takes a shine to him. She's played by the sassy MyAnna Buring (also seen potholing in horror flick The Descent) who dares to take on the Sapphic scourge and convince the lads that women aren't all bad. And watch out for Paul McGann as the exorcist vicar whose doom-mongering makes him a great foil for the blasé Corden.

Too often though, great casting makes up for a lack of inspiration in the writing. For every gag that hits there are three that splatter like vampire innards, which isn't too surprising since the writers mostly ply their trade in TV sketch shows. That would also explain a few missed opportunities, the most glaring when Jimmy's ex-girlfriend (Lucy Gaskell) ventures into the forest to look for him. There's a chance for real tension and gallows humor, but it ends up being sacrificed for a lazy punchline. Other jokes are killed by repetition, like the German girl who can't say 'nein' and the vicar's chronic swearing. Frankly, you can punch holes in this film till it can't stand up, but why bother? Corden and Horne save the day with their own brand of sunshine.